This is an initial submission by a new investigator (Dr. David Sarwer) in response to RFA DK-03- 022 titled "Ancillary Studies to Obesity-Related Clinical Trials." This application is designed to serve as an ancillary study to the Bariatric Surgery Clinical Research Consortium, now referred to as Longitudinal Assessment of Bariatric Surgery (LABS). LABS is a six-center research consortium working in cooperation with National Institutes of Health (NIH) scientific staff to plan, develop, and conduct coordinated clinical,epidemiological, and behavioral research in bariatric surgery. This ancillary study, approved by the LABS Ancillary Study Committee, proposes to investigate changes in sexual function, sex hormones, body image, and marital functioning in 120 LABS participants and compare them with responses in 120 extremely obese individuals who do not undergo bariatric surgery. Patients who seek bariatric surgery are often motivated to lose weight to improve their physical health. Many patients also pursue surgery and the resulting weight loss to improve their quality of life and, morespecifically, their physical appearance and body image. Studies indicate that bariatric surgery confers these benefits. Few studies, however, have investigated more specific aspects of extremely obese individuals'quality of life, including sexual function. Similarly, there has been little investigation of changes in sex hormones following bariatric surgery and their potential relationship with changes in sexual function. The LABS consortium provides an excellent opportunity to investigate long-term changes in sexual function, sex hormones, body image, and marital satisfaction in individuals who undergo bariatric surgery for extreme obesity. The proposed study will assess changes in these domains as compared to changes experienced by extremely obese individuals who do not undergo bariatric surgery. The proposed study is innovative, as it will provide new and important information on the long-term effects of bariatric surgery on these important areas of quality of life.